This invention relates generally to a crop residue spreader for an agricultural combine, and more particularly, to rotary crop accelerating apparatus for a spreader, the accelerating apparatus including blades which are supported advantageously for optimally distributing loads generated by contact with and acceleration of crop residue such as chaff and straw, and which blades are optimally shaped and located for receiving and accelerating flows of chaff and optionally straw for discharge from the spreader and distribution over an agricultural field.
Rotary crop residue spreaders for agricultural combines are well known in the art. Reference in this regard, Clarke U.S. Pat. No. 4,591,102, issued May 22, 1986, which discloses a representative chaff spreader for a combine harvester including rotary crop accelerating apparatus comprising fans having a plurality of radially extending blades, the fans each being rotatable for propelling crop residue outwardly from a housing partially containing the fan. Other known spreaders utilize a rotating disk supporting a plurality of radially extending blades or impellers on one surface thereof for engaging and propelling crop residue or other material in a radially outward direction. Reference in this regard, Scott et al. U.S. Pat. No. 4,892,504, issued Jan. 9, 1990 to Gehl Company.
An observed shortcoming, however, of both the known fan type accelerating apparatus and the known disk type accelerating apparatus, is that loads generated by the rotation of the fan blades and from contact with the crop residue are not ideally or optimally transferred to supporting structure such as a central hub or casting in the instance of the fan type apparatus, and to the supporting disk in the instance of the disk type apparatus, such that the blades will typically have a relatively narrow profile and the spreaders will have a less than optimal capacity, operability and durability. Still further, it is desired to provide a crop accelerating apparatus for a spreader which is better capable of handling different or mixed crop residue flows such as straw and chaff. Straw, for the present purposes, typically includes bean and grain stalks and stems, corn cobs, weeds, vines, and the like, is typically relatively heavy, and is delivered to the spreader from above. Chaff, which typically includes more intimately associated aspects of the bean, grain or other crop being harvested, is typically blown or otherwise delivered to the spreader from a more forward direction, comprises small constituent elements compared to the straw flow, and is typically less dense or voluminous compared to the straw flow.
Therefore, what is sought is rotary crop residue accelerating apparatus for a spreader of a agricultural combine which overcomes the shortcomings and provides the advantageous properties discussed above.
According to one preferred aspect of the present invention, rotary accelerating apparatus for a crop residue spreader of an agricultural combine which overcomes the shortcomings and provides the advantageous properties discussed above, is disclosed. The present rotary accelerating apparatus is particularly will adapted for receiving flows of chaff and straw from different directions and having different densities and other characteristics, and accelerating the flows and discharging them from the spreader together and relatively evenly over an agricultural field. The present apparatus includes a hub mountable on a rotatable member of the spreader, such as a shaft of a hydraulic, electric or other motor, for rotation therewith in a predetermined rotational direction about a rotational axis oriented generally horizontally or at a small acute angle to horizontal. The apparatus includes a plurality of blades disposed at angularly spaced locations around the rotational axis and extending radially outwardly from the axis and the hub. Each of the blades has a surface oriented to face in the rotational direction, the surface having a first axial edge and a second axial edge axially spaced from and opposite of the first axial edge. Each of the blades additionally includes a mounting portion disposed intermediate the first and second axial edges. The apparatus includes a plurality of arms connected to and extending radially outwardly from the hub at angularly spaced locations around the rotational axis and connected to the mounting portion of the blades, respectively, for supporting the blades for rotation with the hub about the axis. The surface of each of the blades includes a first surface portion extending from the first axial edge to about the mounting portion and having a predetermined first axial extent therebetween and a predetermined first radial extent relative to the rotational axis, and a second surface portion extending from about the mounting portion to the second axial edge having a predetermined second axial extent therebetween and a predetermined second radial extent, the first axial extent being substantially greater than the second axial extent and the first radial extent being substantially greater than the second radial extent, and wherein the first and second surface portions of the blade are positioned one relative to the other in relative to the rotational axis such that when the hub is mounted to the rotational member, the first surface portions of the blades will be located primarily in the path of the flow of chaff from the combine and the second surface portions will be located primarily in the path of the flow of straw from the combine such that more desirable load distribution and crop residue handling properties are achieved. For instance, centrifugal forces resulting from the rotation, and applied forces resulting from contact with the crop residue have been found to be better distributed and transferred to the arms, hub and rotatable members, resulting in improved durability. The profile of the blades also have been found to provide better integration of the different crop residue flows, such that there is less rejection of the chaff by the heavier, bulkier straw and less accumulation of the crop residue in the spreader.
According to a preferred aspect of the invention, each of the blades of the rotary accelerating apparatus has an axially extending radially outermost edge having a stepped or notched shape including a first edge portion extending along the first surface portion and a second edge portion extending along the second surface portion radially inwardly of the first edge portion, which configuration has been found to favorably affect the load distribution and integration of the crop residue flows, as well as the outflow of the accelerated crop residue. The larger diameter first surface portion of the blades protruding more forwardly facilitates the engagement, acceleration, and distribution of the chaff for a wide and uniform distribution thereof over the field. The smaller diameter more rearward second surface portion of the blades provides an improved means for engaging the straw and containing the straw in the upwardly open inlet region of the spreader, resulting in less rejection, and other adverse effects on the chaff flow along the more forward first surface portions of the blades. As a result, a consolidated advantageous effect on chaff and straw distribution over a field is achieved. As another advantage, the location of the mounting portion of the blades and connection to the supporting arms and hub is not constrained, and can be varied as required to achieve a desired force loading.
According to another preferred aspect of the invention, rotary accelerating apparatus for a crop residue spreader of an agricultural combine is disclosed, which includes a hub mountable on a rotatable member of the spreader for rotation therewith in a predetermined rotational direction about a rotational axis, the hub having a first axial end portion and a second axial end portion opposite of and axially spaced from the first axial end portion; a mounting bracket mounted to the first axial end portion of the hub and including a plurality of radially outwardly extending portions at spaced locations around the rotational axis or hub; a plurality of blades mounted to the radially outwardly extending portions, respectively, for rotation therewith about the rotational axis, each of the blades having a first axial edge portion located about axially coincident with the axial end portion of the hub and the radially outwardly extending portions, and a second axial edge portion opposite the first axial edge portion; and a disk mounted to at least some of the second axial edge portions of the blades and for rotation therewith for enclosing an adjacent axial end of spaces between adjacent ones of the blade.
A principle advantage of this embodiment is the support of the disk by the blades as opposed to the reverse, that is, the support of the blades by the disk, it having been found that loads resulting from the rotation and contact with the crop residue being more favorably distributed by the present arrangement. This arrangement also demonstrates the variability of the location of the attachment of the blades to the arms.